Conventionally, FinFET fabrication employs implants such as halo and extension implants which result in the fin surface being amorpharized, i.e., converted from a crystalline material into an amorphous one. Clean up steps following the implants attack the amorpharized fin surface making the fin thinner, particularly for multi-Vt flow devices which employ many halo and extension implants. The reduced thickness fin, particularly the portion disposed under spacers or sidewalls disposed adjacent to the sides of the gate, increases resistance which degrades the device performance.
There is a need for improved methods for forming FinFETs with reduced series resistance.